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.Dd $Mdocdate: June 5 2013 $
.Dt GETGROUPLIST 3
.Os
.Sh NAME
.Nm getgrouplist
.Nd calculate group access list
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn getgrouplist "const char *name" "gid_t basegid" "gid_t *groups" "int *ngroups"
.Sh DESCRIPTION
The
.Fn getgrouplist
function reads through the
.Xr group 5
file and calculates the group access list for the user specified in
.Fa name .
The
.Fa basegid
is automatically included in the groups list.
Typically this value is given as
the group number from the password file.
.Pp
If YP is active and the group file contains no exclusions, the
.Xr netid 5
file and the
.Pa netid.byname
YP map will be used in addition to the group file.
If the group file contains at least one exclusion, the
.Pa group.byname
YP map will be used in addition to the group file.
.Pp
The resulting group list is returned in the integer array pointed to by
.Fa groups .
The caller specifies the size of the
.Fa groups
array in the integer pointed to by
.Fa ngroups ;
the actual number of groups found is returned in
.Fa ngroups .
.Sh RETURN VALUES
The
.Fn getgrouplist
function returns 0 if successful and \-1 if the size of the group list is
too small to hold all the user's groups.
Here, the group array will be filled with as many groups as will fit.
.Sh FILES
.Bl -tag -width /etc/group -compact
.It Pa /etc/group
group database file
.It Pa /etc/netid
static group lists to override YP data
.El
.Sh SEE ALSO
.Xr setgroups 2 ,
.Xr initgroups 3 ,
.Xr yp_match 3 ,
.Xr group 5 ,
.Xr netid 5 ,
.Xr yp 8
.Sh HISTORY
The
.Fn getgrouplist
function first appeared in
.Bx 4.4 .
.Sh BUGS
The
.Fn getgrouplist
function uses the routines based on
.Xr getgrent 3 .
If the invoking program uses any of these routines,
the group structure will be overwritten in the call to
.Fn getgrouplist .
